<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <title>2</title>
</head>
 
<body>
 <canvas id="canvas" style="border: 1px solid red; width: 80px; height: 40px;"></canvas>
 <span id="yanzhengma"></span><button onclick="getVerification()">看不清</button>
 <script>
 function randomColor() {
 var colorValue = "0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f";
 var colorArray = colorValue.split(",");
 var color = "#";
 for (var i = 0; i < 6; i++) {
 color += colorArray[Math.floor(Math.random() * 16)];
 }
 return color;
 }
 function getRandomNum(n){
 return parseInt(Math.random() * n); 
 }
 function getVerification() {
 var ctx = document.getElementById("canvas").getContext("2d");
 ctx.clearRect(0,0, 400, 400);
 // 设置字体
 ctx.font = "128px bold 黑体";
 // 设置垂直对齐方式
 ctx.textBaseline = "top";
 // 设置颜色
 ctx.fillStyle = randomColor();
 // 绘制文字（参数：要写的字，x坐标，y坐标）
 ctx.fillText(getRandomNum(10), 0, getRandomNum(50));
 ctx.fillStyle = randomColor();
 ctx.fillText(getRandomNum(10), 50, getRandomNum(50));
 ctx.fillStyle = randomColor();
 ctx.fillText(getRandomNum(10), 100, getRandomNum(50));
 ctx.fillStyle = randomColor();
 ctx.fillText(getRandomNum(10), 150, getRandomNum(50));
 }
 getVerification();
 </script>
</body>
</html>